25 research outputs found

    Novel Domain Wall and Minkowski Vacua of D=9 Maximal SO(2) Gauged Supergravity

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    We show that a generalised reduction of D=10 IIB supergravity leads, in a certain limit, to a maximally extended SO(2) gauged supergravity in D=9. We show the scalar potential of this model allows both Minkowski and a new type of domain wall solution to the Bogomol'nyi equations. We relate these vacua to type IIB D-branes.Comment: 28 pages, 1 figure, Latex2

    Effective Field Theories and Inflation

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    We investigate the possible influence of very-high-energy physics on inflationary predictions focussing on whether effective field theories can allow effects which are parametrically larger than order H^2/M^2, where M is the scale of heavy physics and H is the Hubble scale at horizon exit. By investigating supersymmetric hybrid inflation models, we show that decoupling does not preclude heavy-physics having effects for the CMB with observable size even if H^2/M^2 << O(1%), although their presence can only be inferred from observations given some a priori assumptions about the inflationary mechanism. Our analysis differs from the results of hep-th/0210233, in which other kinds of heavy-physics effects were found which could alter inflationary predictions for CMB fluctuations, inasmuch as the heavy-physics can be integrated out here to produce an effective field theory description of low-energy physics. We argue, as in hep-th/0210233, that the potential presence of heavy-physics effects in the CMB does not alter the predictions of inflation for generic models, but does make the search for deviations from standard predictions worthwhile.Comment: 19 pages, LaTeX, no figures, uses JHEP

    Inhibition of pRb phosphorylation and cell-cycle progression by a 20-residue peptide derived from p16CDKN2/INK4A

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    AbstractBackground: The CDKN2/INK4A tumour suppressor gene is deleted or mutated in a large number of human cancers. Overexpression of its product, p16, has been shown to block the transition through the G1/S phase of the cell cycle in a pRb-dependent fashion by inhibiting the cyclin D-dependent kinases cdk4 and cdk6. Reconstitution of p16 function in transformed cells is therefore an attractive target for anti-cancer drug design.Results We have identified a 20-residue synthetic peptide — corresponding to amino acids 84–103 of p16 – that interacts with cdk4 and cdk6, and inhibits the in vitro phosphorylation of pRb mediated by cdk4–cyclin D1. The amino-acid residues of p16 important for its interaction with cdk4 and cdk6 and for the inhibition of pRb phosphorylation were defined by an alanine substitution series of peptides. In normal proliferating human HaCaT cells and in cells released from serum starvation, entry into S phase was blocked by the p16-derived peptide when it was coupled to a small peptide carrier molecule and applied directly to the tissue culture medium. This cell-cycle block was associated with an inhibition of pRb phosphorylation in vivo.Conclusion These results demonstrate that a p16-derived peptide can mediate three of the known functions of p16: firstly, it interacts with cdk4 and cdk6; secondly, it inhibits pRb phosphorylation in vitro and in vivo; and thirdly, it blocks entry into S phase. The fact that one small synthetic peptide can enter the cells directly from the tissue culture medium to inhibit pRb phosphorylation and block cell-cycle progression makes this an attractive approach for future peptidometic drug design. Our results suggest a novel and exciting means by which the function of the p16 suppressor gene can be restored in human tumours

    Phenomenology of Low Quantum Gravity Scale Models

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    We study some phenomenological implications of models where the scale of quantum gravity effects lies much below the four-dimensional Planck scale. These models arise from M-theory vacua where either the internal space volume is large or the string coupling is very small. We provide a critical analysis of ways to unify electroweak, strong and gravitational interactions in M-theory. We discuss the relations between different scales in two M-vacua: Type I strings and Ho\v rava-Witten supergravity models. The latter allows possibilities for an eleven-dimensional scale at TeV energies with one large dimension below separating our four-dimensional world from a hidden one. Different mechanisms for breaking supersymmetry (gravity mediated, gauge mediated and Scherk-Schwarz mechanisms) are discussed in this framework. Some phenomenological issues such as dark matter (with masses that may vary in time), origin of neutrino masses and axion scale are discussed. We suggest that these are indications that the string scale may be lying in the 1010101410^{10} - 10^{14} GeV region.Comment: 32 pages, latex. Minor corrections and improved referencin

    Comparative allergology: Aspects of sensitization, cross-sensitization and establishment of diagnostic tools

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    Allergien, welche eine IgE Hypersensitivität darstellen, sind in den letzten Jahrzenten immer häufiger aufgetreten und können nicht nur Menschen betreffen, sondern auch Tiere wie Hunde und Pferde. Die vergleichende Allergologie beschäftigt sich mit dem Vergleich der menschlichen und tierischen Allergien. Der Fokus liegt hierbei vor allem auf allergischen Krankheiten und ihren Symptomen, den Quellen allergener Stoffe und ihre Detektionsverfahren, welche gemeinsam eine angemessene Therapie ermöglichen sollen. Das übergeordnete Ziel dieser Arbeit war daher die Anpassung eines molekularen Detektionsverfahrens auf die spezifischen Anforderungen in der Veterinärmedizin. Zuerst wurde eine der Hauptquellen für Allergien, die Hausstaubmilbe, einer detaillierten Untersuchung der enzymatischen Aktivität und der bevorzugten Bedingungen dieser unterzogen. Des Weiteren war es vor allem auch das Ziel, mit dem neuen Verfahren des ImmunoCAP ISAC131 Mikrochip ein neues und modernes Detektionsverfahren für den veterinärmedizinischen Bereich zu etablieren, welches es ermöglicht IgE Sensibilisierungen gegen einzelne spezifische Allergenmoleküle zu detektieren. Die Experimente ergaben, dass Hausstaubmilben Extrakte durch enzymatische Aktivität bei einem breiten pH und Temperatur-Spektrum eine Rolle bei der Zerstörung der Hautbarriere spielen. Zusätzlich zu der bereits bekannten enzymatischen Aktivität von Der p 1, konnten zahlreiche Proteasen wie auch Hexosaminidase mit hoher enzymatischer Aktivität nachgewiesen werden. Unter alkalischen Bedingungen, wie sie auch bei Entzündungen oder unter Einfluß einiger Detergentien vorzufinden sind, war deren enzymatische Aktivität besonders erhöht. Die getesteten Hausstaubmilben Extrakte führten auch zu einer IgE abhängigen Degranulation caniner Mastzellen und bewiesen somit auch ihre Bedeutung als Allergenquelle für Hunde. Der im Humanmedizin Bereich etablierte ImmunoCAP ISAC Chip, welcher kommerziell mit 112 einzelnen Allergenmolekülen hergestellt wird, wurde für die Anwendung im Veterinärbereich mit zusätzlichen 19 Allergenmolekülen bestückt, welche in der klinischen Allergiediagnostik für den Hund, die Katze oder das Pferd eine relevante Rolle spielen. Schließlich wurde so ein ISAC Chip mit 131 verschiedenen Allergenmolekülen (ISAC131) erstellt und etabliert. Das Hauptziel dieser Arbeit bestand darin die innovative ISAC131 Technologie für die Veterinärdiagnostik zu entwickeln und erstmals anzuwenden. 51 Pferde aus drei geographischen Regionen wurden mit dem ISAC131 Chip getestet. Unabhängig von ihrem Gesundheitsstatus konnten individuelle IgE abhängige Muster bei den einzelnen Pferdepatienten beobachtet werden. Diese Chip Ergebnisse bestätigten zum Teil bereits bekannte regelmäßig vorkommende Allergene wie das Cyn d 1 Allergen des Bermudagrases, oder Aln g 1, ein Pollenallergen der Erle. Das dominierende Allergen war jedoch Fag e 2, ein Buchweizenallergen, für welches spezifisches IgE in 38 der 51 getesteten Pferde nachgewiesen werden konnte. Die Ergebnisse eröffnen daher nicht nur die Verwendung eines neuen Detektionsverfahren für den Veterinärbereich, sondern zeigen möglicherweise auch eine neue wichtige Allergenquelle auf, den Buchweizen. Zusammenfassend gibt diese Arbeit einen Überblick über das immer wichtiger werdende Feld der vergleichenden Allergologie. Zum Einen konnte gezeigt werden, dass unter alkalischen Bedingungen Hausstaubmilben Extrakte eine erhöhte Hautirritation begünstigen. Zum Anderen, konnte erstmalig der auf den Veterinärbereich zugeschnittener ImmunoCAP ISAC131 Chip bei der Allergiediagnose beim Pferd angewendet werden. Die Arbeit ermöglicht somit einen Schritt vorwärts zu einer neuen präzisen Detektionsmöglichkeit im Veterinärbereich.The prevalence of allergy IgE-mediated hypersensitivity has increased not only in humans, also in companion animals like dogs and horses. The field of comparative allergology investigates and compares allergies in humans and animals, focusing especially on allergic diseases and their symptoms, the allergen sources and the specific diagnostic detection of the responsible allergen enabling the appropriate therapy. The overall goal of this thesis was to apply molecular analyses in veterinary allergology. The first aim, after a review of the actual comparative allergology conditions, was to investigate the enzymatic activity of a major allergen source in humans and animals, house dust mite (HDM). The second aim was to establish component-resolved microchip technology for equine allergy diagnosis, to reveal the impact of molecular allergens as sensitizers in these animals. We find that the enzymatic activity of house dust mite extracts can play an important role in skin barrier disruption under a wide range of pH and temperature conditions. We observe that in addition to the already-known Der p 1 enzymatic activity, enzymatic activity is caused by several proteases and hexosaminidase. An alkaline milieu like evoked by inflammations or detergents favours higher enzymatic activity of HDM extracts and consequently increases the degradation of the extracellular matrix, whereas different temperatures seem to have a minor impact on the activity. These tested HDM extracts also induced IgE-dependent degranulation of canine mast cells, thus corroborating the importance of HDM as an allergen source in dogs. Subsequently, we use a new molecular technology, the ImmunoCAP ISAC chip. The commercial chip contains 112 allergen molecules, whereas for veterinary use it was tailored by adding additional nineteen allergen molecules that are known to be more relevant for veterinary allergy diagnosis. The custom-designed ISAC chip finally contained 131 allergen molecules and was termed ISAC131. The main aim was consequently to establish the allergen microarray technology for veterinary diagnosis. Fifty-one horses from three geographical regions were tested on the custom-designed ISAC131 microarray. Individual IgE-binding patterns could be observed, partly confirming common known allergens like Cyn d 1 from Bermuda grass and Aln g 1 from alder pollen. The most dominant allergen, however, was Fag e 2 from buckwheat represented by 38 of 51 horses. These results mark buckwheat as a possible allergen source not only for humans, but also for animals. Overall, this thesis provides new aspects in comparative allergology. It not only clarifies under which conditions house dust mite extracts may disrupt the skin barrier, it also establishes an improved version of the ImmunoCAP ISAC chip test enabling a comparison of a huge range of common allergens in humans and to improve allergy diagnosis in veterinary allergology. This method may be a step towards more precise diagnosis in allergy-affected animals.submitted by Lukas EinhornAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersMedizinische Universität Wien, Diss., 2018(VLID)309274

    Gender aspects in allergies of pets – A secondary publication and update

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    Allergies need not only affect humans; this multifactorial and complex disease can also affect animals. Comparative allergology investigates the many similarities between the pathogenesis, clinics, diagnosis, and therapy of the disorders in humans and pet animals. In contrast to human allergy research, the veterinary field lacks access to a central database, which means there are no cohort studies published. This limits not only the research on breed and regional differences in allergies, but also further studies on the impact of gender in allergies of domestic animals. Moreover, domestic cats, dogs and male horses are castrated in most cases, which neutralises any effects of sexual hormones. In this review article a few interesting findings regarding gender aspects in companion animals were extracted from current literature. In summary, there is a lack of data on gender effects on allergies in cats, dogs or horses. Keywords: Atopic dermatitis, Canine, Cat, Dog, Gender, Horse, Pe

    Innate function of house dust mite allergens: robust enzymatic degradation of extracellular matrix at elevated pH

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    Background Exposure to the house dust mite Dermatophagoides pteronyssinus (D.p.) increases the risk for developing allergic diseases in humans and their best friends, the dogs. Here, we explored whether this allergenic mite via its enzymes may impact the cutaneous extracellular matrix (ECM), which critically determines epithelial barrier integrity both structurally and functionally.Methods Two extracts obtained from either dust-purified or cultured D.p. bodies were used in the present study. To assess the potential impact of D.p. on protein components of the ECM, proteolytic activity of the D.p. extracts were determined by casein and gelatin gel zymography, and their N-acetyl-β-hexosaminidase activity determined colorimetrically. In addition, IgE-dependent and innate degranulation potential of D.p. was examined in canine MPT-1 mast cells and neurite outgrowth assay using rat pheochromocytoma PC-12 cells.Results In gel zymography, both extracts digested the substrates casein and gelatin in a dose-dependent manner, especially at alkaline pH, and effective in a wide range of temperatures (30 °C−42 °C). In particular, a 25-kDa band corresponding to Der p 1, the major D.p. allergen for humans, was found enzymatically active in both casein and gelatin gels regardless of the presence of metal ions and of alkaline conditions. Besides protease activity, N-acetyl-β-hexosaminidase activity was detected in both extracts, suggesting that D.p. affects the cutaneous ECM through deteriorating both proteins and glycosaminoglycans. While both D.p. extracts induced IgE-dependent mast cell degranulation, much less innate effects on mast- and neuronal cells were observed.Conclusions Our data highlight that D.p. is a robust source of several distinct enzymes with protease- and N-acetyl-β-hexosaminidase activities. In alkaline milieu they can degrade components of the ECM. Therefore, D.p. may contribute to epithelial barrier disruption especially when the skin surface pH is elevated. Keywords: Dermatophagoides pteronyssinus, Allergens, Epithelial barrier, Extracellular matrix, Proteases, N-acetyl-β-hexosaminidas
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